Physicists at the universities of Bath, Bristol and Leeds in the UK have discovered a way to precisely control the pattern of magnetic fields in thin magnetic films, which can be used to store information, thus pointing the way for to a new generation of more powerful and permanent data storage chips in computers.
The work has important consequences for the IT industry, as current memory storage technology has limited scope for further development. The density with which information can be stored magnetically in hard drives is reaching a natural limit related to the size of the magnetic particles used, while the much faster random access memory loses the information stored when the power is switched off.
The key advance of the research is in developing ways to use high-energy beams of gallium ions to control the direction of the magnetic field in regions of cobalt films just a few atoms thick. The direction of the field can be used to store information, with “up” or “down” corresponding to the “1” or “0” that form the basis of binary information storage in computers.
The physicists have shown that the direction of these magnetic areas can be read by measuring their electrical resistance. This is much faster than the system for reading information on current hard drives. The magnetic state can be switched from “up” to “down” with a short pulse of electrical current, fulfilling all the requirements for a fast magnetic memory cell.
Simon Bending, of the University of Bath's Department of Physics, said the results are important because they suggest a new route for developing high-density magnetic memory chips which will not lose information when the power is switched off. “For the first time data will be written and read very fast using only electrical currents.”
Several companies have built prototypes of magnetic random access memory chips, which use the stray magnetic fields generated by wires that carry a high electrical current to switch the data state from “up” to “down”. But this greatly limits the density of information storage.
In contrast, Bending’s approach would allow the manufacture of magnetic memory chips with much higher packing densities, which can operate many times as fast.